My R700 338 Rum is all factory aside from the timney trigger and is bedded in an HS Precision stock with their DBM. As to accuracy before and after I couldn't say as I never shot it before the swap but it will shoot the 210 TSX and 250 scenars under 3/4" for 5 at 100 yds. I have never shot it past 550yds on game but I sure works well at killing.
I got a good deal on the stock and DBM and have been perfectly happy with it.